Cat not eating and vomiting

Hello :) I hope everyone is well!   My 1 year old male cat has suddenly stopped eating since last night - he's denying everything I offer him but he is still drinking water. he keeps throwing up clear liquid.   He was visiting my mom over the weekend and while playing outside accidentally ate some grass before my mom stopped him.   Could the grass be what's causing this??  

Hello - sometimes, when animals are feeling sick, they do munch grass to try to ease their stomachs (and then throw it up).  However, it is unlikely to be grass that is the actual cause of the sickness.  Continued vomiting can lead to dehydration, so we would reccommend reporting this to your vet as a matter of urgency in order that they can assess whether or not the patient needs to be on a drip.